It's been up for debate for some time whether it really gives more power and mpg. While it does take the strain off the crank, it's adding it back on in the form of additional load on the alternator, which then has t pull more power from the crank. However, Collinsperformance wrote a GREAT write-up on how to convert over to a Ford Taurus fan, which moves the most air than any other factory or aftermarket fan available. Here's the link to his write-up: http://www.gmtruckclub.com/forum/showthread.php?t=6800